Glass Transition in a Two-Dimensional Electron System in Silicon in a Parallel Magnetic Field

TL;DR

This study investigates the glass transition in a two-dimensional electron system in silicon under parallel magnetic fields, revealing that charge degrees of freedom drive glassy behavior near the metal-insulator transition, independent of spin polarization at high fields.

Contribution

It demonstrates that charge, not spin, degrees of freedom govern glassy ordering in the 2DES near the MIT, with the glass transition density increasing with magnetic field at low fields.

Findings

Glass transition persists up to 9 T magnetic field.

Charge degrees of freedom drive glassy behavior.

Critical densities increase with magnetic field at low B.

Abstract

Studies of low-frequency resistance noise show that the glassy freezing of the two-dimensional electron system (2DES) in Si in the vicinity of the metal-insulator transition (MIT) persists in parallel magnetic fields B of up to 9 T. At low B, both the glass transition density $n_g$ and $n_c$, the critical density for the MIT, increase with B such that the width of the metallic glass phase ($n_c<n_s<n_g$) increases with B. At higher B, where the 2DES is spin polarized, $n_c$ and $n_g$ no longer depend on B. Our results demonstrate that charge, as opposed to spin, degrees of freedom are responsible for glassy ordering of the 2DES near the MIT.